Mandrel for forming tubes



March 16, 1937. A. P. DIESCHER MANDREL FOR FORMING TUBES Filed Jan. 4, 1936 RH A A v wwvw v 14-". ATTORNEYI.

' 20 wall and of. smaller diame r.

' .when desired.

Patented Msr..18,fl937 UNITED STATE s PATENT OFFICE l non some runes Aulfiut P. Diesch l', Pittsburgh, Pa assignmto escher Tube (Mills, ms, mama, 2a., a

corporation of Delaware Application 1mm. 1930; Serial No. 81,514 '1 Claims. (01. 80-13);

-'I' hisyinvention relates to mandrels used in making seamless tubes, and more particularly to mandrels having a short working section devtachably connected to amandreibar. 4 5 In my Patent No. 2,006,336 and my 'patentapplication Serial No. 694,284, filed October. 19,

I 1933, there are shown: mills for the cross rollq ing oistubes in which axial movementoi a mandrel relative to the rolls is controlled from the inlet side and from the outlet side, respectively. oi the mill. with this type or mill-it is desirable, particularlydn the production or large diameter tubes, to utilize only a comparativelyv short portion or the mandrel as a working memher. -'1herefore, it is necessary that only this short working-portion be made of heavy wall producing the desired ,-int ernal diameter. -oi a tube. The rest of the mandrel may be of lighter Accordingly, it is and have a diameter equal to that required igr desirable to-make the-ma el'in two parts; that working section of the mandrel. The outerend is, a workingsection det'achabl'y connected to a bar or stem, preferably. by screw threads, sothat the former can be removed and replaced 'when worn or damaged without having to replace the entire mandrel. However, as themandrel may under various working conditions be rotated either taster or slower than the tube.

. there is danger of its working section being unso screwed ironr-the stem. On the other hand,

they should ot be connected together in such a manner t It isan object of this invention to provide a composite mandrel, having aworking section detachably-connected to a stem, in which means is provided -ior locking-the two parts together in such a manner thatthey can not become separated'accidentaliy.

40 Other objects are to provide such -a 'mandrel in which the ,working section can be easily and quickly detached from the stem when desired, and in which the joint between the working section and stem is substantiallywater-tight to of this working section is provided with a reduced portion 5 angular in 'cross section for receiving a wrench by which member 4 can be screwed on or of! the stem without injuring the surface of that'membe'r. Sleeve 3 .of the'stem provides support for the working section and.

.aidsin'guiding it onto the tapered threads 015- 'the stem when the mandrel ,is being assembled.

As mm 54 is'the only workingportion or the mandrel, e stem can have a smaller diameter and a thinner walland be made of less expensi've steel than. the working portion, thereby; decreasing the cost and weight oi the mandrel as a whole, as well as'oLits manipulatingand con;-

trol apparatus. 1,.

Extending axially through the stem and into here 8 of the working section is a water. teed pipe t itis dimcult to separate them Twhich is centeredin the stem by any Sistin 30 means, such as-by star wheel guides 8 loosely .miounted on the pipe between collars 9 secured to the pipe (Fig. 3). Mandrel cooling water flow? ing into the hollow working section 4 from the "1'0 facilitateboring outer end of thispi the stemlinthe circulates backthrough between it and the pipe.

e working sectionandto .provide for driving out the water pipe incasethatbecomes,bore6 extends entirely through the working'section with its outer end .closedby a screw plug lihavinga permit themandrel to bewater-cooled without.

harmful leakage at the joint. The preferred embodiment oi the invention is illustrated in the accompanying drawing in which Fig. l is a side view,partly in section, 01,

a composite mandrel; Fig. 2 is aview similar. to

projecting, angular head adapted to receive a. wreneh e x It is a feature of this invention that the workingsection oi the mandrel-is lockedv to the stem 45 r in such manner; as to prevent the two sections r Lshowing the working portion of thee mam ,drel unlocked from its stem; Figs. 3,- 4 and-5 8;?

' cross sections takenon the lines III-III, IV-

and V- V, respectively, oi Fig. l; and Fig 6 is an interior view taken on the line VI-VI of Fig. 2;

Referring to Fig. 1 ofthe drawing, a tubular mandrelstenf-l is connected at its rear end to' teed control means, not showmior controlling its movement axiallyrelative to cross rolls or 50 a tube elongating mill. The feed control means.

.water pipe 1 between a by providing their interior walls witha plurality irom being unscrewed .or loosenedwhen in service, the lock being such that it does not interfere with quick and easy removal or the working section from the stem when desired. This is preferably accomplished by making the inside diameter of the working section Q adjacent the outer end oi" the tu ular stemsubstantially the same as that of the outer end .otthe stem, and

55 of aligned longitudinally" extending recesses or grooves l2 and I3 (Fig. 6) that form splines l4 and I8 extending radially' inward. Rotatably mounted on anddongitudinally movable (with pair oi! collars i'l se- -1.

operative position cured thereto, is a generally cylindrical locking member l8 provided about its periphery with a plurality of radial splines or keys I9'extending longitudinally thereof and capable of registering simultaneously with the splines and grooves in both the stem and working section" (Figs. 1, 4 and 5), whereby the latter is prevented from being rotated relative to'the stem.

Thetlocking member is held in looking position ,by water pipe 1, the outer end of which is locked against movement axially of the mandrel by any suitable means. As will be seen in Figs. 4 and 5, the grooves in the locking member and in the mandrel sections'are deeper than the corresponding splines so'as to leave spaces 2| through which water can flow back .past the locking member from the bore of the working section. It is unnecessary to have a rotary pipe 'joint where the outer end of the water pipe is connected to its water supply, because star guides 8 and locking member l8 are loosely mounted on the pipe-to permit the mandrel to freely rotate without rotating the pipe.

The working section of the. mandrel is unlocked from the stem, to, permit them to be separated, by retracting the water pipe to pull the locking member entirely into the stem and out of engagement with the working section, as shown in Fig. 2. In reassembling the mandrel the working section is not screwed up tight on.

and grooves into alignment with those oi the stem to let the locking member he slid forward into locking position. To make it easier for the keys on the locking member to enter the corresponding grooves in the working section, the ends of the splines and keys are tapered, as shown in Fig. 6. r

Amandrel constructed in accordance with thisinvention is relatively inexpensive because only theshort working section need be made of a size and metal capable of withstanding the forces to which it is'subjected in use. When in use, the working section is securely locked to the stem so that they can not loosen or come apart accidentally, and the joint issubstantially water-tight. The locking means is easily disengaged from the working'secti'on, when desired, to permit the latter to be quicklyremoved from the stem.

According to the provisions of the patent statutes, I. have explained the principle and construction of my invention and have illustrated and described what I now consider to represent its best em ent. However, I desire to have it understood that, within --the scope of the appended claims, the invention-may be practiced otherwise than as specifically illus-- 'trated and described.

I claim:

1. A mandrel comprising a stem member, a working member detachably connected to one end thereof, one of said members being provided with an axial bore extending from end to end, means disposed in said bore for locking said members together against rotation relative to each other, and means disposed in said bore for moving said locking means into and out oi.

to lock and release said members.

2. A mandrel comprising a stem member, a working member detachably connected to one end thereof, one of said'members being prolocking said memberstogether against rotation relative to each other, and means disposed in said bore for sliding said locking means into and out of locking position.

3. A mandrel comprising a stem member, a working member detachably connected to the outer end thereof, one'of said members being provided with an axial bore extending from end to end, the portion of the other of said members adjacent said bore being provided with a recess having detents, locking means slidably and nonrotatably disposed in said bore and projecting into said recess for holding said members against rotation relative to each other, and means disposed in said bore and operable from an end thereof for withdrawing said locking means from said recess whereby to permit said members to be rotated relative to each other.

4. A mandrel comprising a tubular stem, a

hollow working member detachably connected to one end thereof, a locking member slidably disposed in the stem adjacent said working member and being provided at it's periphery with a key, the stem being provided interiorly with a longitudinal groove for receiving said key,

said working member being provided interiorly with a key-receivinggroove in alignment with said stem groove, and means disposed in said stern for sliding a portion or said key into. and

out, of. said working member groove.

5. A mandrel for use in a tube mill, comprising a tubular stem, a hollow working member screwed on the outer end of the stem, the adjoining ends of said stemand working member being provided .interiorly with aligned longitudinal' grooves, a locking member slidably disposed in said stem and provided at its periphery with a plurality of radial keys registering with said grooves for locking said working member upon the stem, 'an axially movable water .pipe disposed inthe' stem, and means for connecting said locking'member to said pipe whereby the locking member can be withdrawn from said working member by the pipe.-

6. A mandrel for use in a tube mill, comprising a tubular stem, a hollowworking member screwed on the outer end of the stem, the ad joining ends of said stem and working member I being provided interiorly with aligned longitudinal grooves, an axially movable water pipe disposed in the stem, a locking member rotatably mounted on said pipe'and slidably disposed in said stem, and means for holding said locking member against movement longitudinally of the pipe, said. locking member being provided at its periphery with a plurality oi radial keys registering with said grooves for normally looking said working member on said stem.

7. A mandrel comprising a stem member, a working member detachably connected to one end thereof, one of said members being provided with an axial bore extending from end to end, means disposed in said bore for positively locking said members together, and means disposed in said bore for moving said locking means into and out of operative positionto lock and release said members, it being necessary for said locking means to be free oijone onsaid members before said members camstart to separate.

AUGUST P. DIESCHIER. 

